RFR: 8301220: Return value of toArray() of Сollection types from java.base should be trusted

[Sergey Tsypanov]

On Thu, 26 Jan 2023 06:46:16 GMT, Glavo <duke at openjdk.org> wrote:

> I checked the `java.base` module, and all the `Collection#toArray()` method of collections be implemented correctly.
> 
> Their return values can be trusted, so many unnecessary array duplication can be eliminated.

You could also have a look into `PriorityQueue.initElementsFromCollection()`

@Glavo I've filed https://bugs.openjdk.org/browse/JDK-8301220 so you can use it for this PR.

src/java.base/share/classes/java/util/concurrent/CopyOnWriteArrayList.java line 746:

> 744:             int len = es.length;
> 745:             Object[] newElements;
> 746:             if (len == 0 && c.getClass().getModule() == Object.class.getModule()) {

I think as soon as we anyway assign the array from trusted collection, we don't need `len == 0` check here any more

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PR: https://git.openjdk.org/jdk/pull/12212